Case Study: Bt Corn Pollen and the Monarch Butterfly By Doug Golick - AgBiosafety Web Coordinator

Purpose: This is a case study introducing students to a real controversy surrounding biotech crops and their effects on Monarch butterflies. Students will review published materials and answer a series of questions to help guide them in making “science-based” decisions on the true affect of biotech crops on the Monarch butterfly. Students will be able to apply some of the basic concepts learned in this lesson to other controversies in the biotech world.

Objectives: Upon completion of this lesson the students will: gain a reinforced understanding of hazard and risk. learn the potential complexity of issues involving risk. learn about risk assessment as it pertains to the monarch butterfly controversy. demonstrate their understanding of argumentation and make a conclusion about the monarch butterfly and Bt corn pollen controversy. Teacher background: In 1999 researchers from Cornell University published a letter in the journal Nature that showed Bt corn pollen had toxic effects on larvae of the monarch butterfly. The caterpillar, or larval stage, of this insect feeds on milkweed plants. Because some milkweed grows next to corn fields, Losey and his Cornell collegues suggested that Bt corn pollen may drift onto milkweed and harm the monarch larvae. Although only a note and not a full scientific investigation, the Cornell letter garnered a tremendous amount of media coverage and gave anti-biotech advocates a poster species for their cause. In the following year the EPA, biotech companies, and university researchers studied the potential impact of Bt corn pollen on the monarch butterfly and related species. Their research findings were published in September 2001 in a series of papers (PNAS, 2001). In this assignment students will be asked to review the research articles starting with the Cornell study. After reading the article students will be asked to answer a series of questions that will help them assess the risk of the Bt corn pollen to the monarch butterfly. At the end students will write a short summary of their conclusions stating an assessment of the impact of Bt corn pollen to the monarch butterfly. Method: 1. Students will be introduced the Bt corn pollen and monarch butterfly controversy through teacher led discussion (information provided in teacher background). 2. Students will be introduced to the concepts of hazard, risk, and risk assessment through teacher led discussion (information provided in teacher background). 3. Students will be given the Case Study: Bt corn and the Monarch butterfly controversy. 4. Students will read papers (available through download or print Online see below) and answer the series of questions provided in the student case study assignment sheet. 5. Students will make a final assessment/decision about the risk and safety of Bt crops and Monarch butterflies. 6. Optional: once assignment is submitted, teacher will lead a class discussion of the students’ findings after doing the case study. Suggested questions for the post-case study discussion: Are Bt crops hazardous? If so, to which organisms? Is the monarch butterfly at risk from the Bt corn pollen? Many other studies have been published on non-target insects other than the monarch butterfly. Why do you think the Losey study received so much attention? Is the monarch butterfly more important than the other insects? Are there other reasons for this attention? Given the results of the studies, what should the future implications be for these crops? Do they need to have the same amount of regulation? Do they need to be regulated more strictly? Assessment: There are several ways this assignment can be assessed. The assignment can be graded strictly on a point basis for correctly answered questions and sufficiently supported argumentation. This would be the case in a take home assignment per individual student or small group. The assignment can also be used as a class discussion where students form small groups to investigate the problem. Groups can then report their results to the class and the instructor can regulate the discussion. In this case learning can be assessed by participation at the group level. The learning goals of this assignment can be seen if students are able to demonstrate a conclusion about the real risk of Bt to monarch, through a step-by-step assessment. Answers to Student Handout Questions: Click here to view answers Articles for Review: There are several articles that are included in this lesson. If you feel that the list is too extensive for your students to read you may exclude the Butterfly Survivor Article, Monarch Butterfly Natural Enemies, Bt Corn and European Corn Borer Information, and Monarch Overwintering Web links. These articles are meant to give the students a broader scope of the problem. It is suggested that the instructor read all the articles for a better understanding of the terms and articles surrounding this case study. John E. Losey, Linda S. Rayor, Maureen E. Carter (Department of Entomology, Cornell University). Transgenic Pollen Harms Monarch Larvae . Nature, 399. May 20, 1999 http://www.biotech-info.net/transpollen.html Steven Milloy. “Butterfly Survivor”, Junkscience.com http://junkscience.com/foxnews/fn082500.htm or http://www.biotechknowledge.com/showlib.php3?uid=3863 Monarch Butterfly Natural Enemies http://www.monarchlab.umn.edu/Research/PNE/pne.html Bt Corn and European Corn Borer Information http://croptechnology.unl.edu/html/startLessonFrame.shtml?LessonID=994877762&category=CropGenetics Selected Monarch Research Papers *To access the monarch papers, your institution must have a subscription* (click here for more info) Mark K. Sears, Richard L. Hellmich, Diane E. Stanley-Horn, Karen S. Oberhauser, John M. Pleasants, Heather R. Mattila, Blair D. Siegfried, and Galen P. Dively. Impact of Bt corn pollen on monarch butterfly populations: A risk assessment PNAS published September 14, 2001, 10.1073/pnas.211329998 ( Agricultural Sciences ) http://www.pnas.org/cgi/content/full/211329998v1 Effects of exposure to event 176 Bacillus thuringiensis corn pollen on monarch and black swallowtail caterpillars under field conditions Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen Corn pollen deposition on milkweeds in and near cornfields Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies Temporal and spatial overlap between monarch larvae and corn pollen Student Assigment Sheet Click here for student handout